I. Field
The following description relates generally to communications systems and more particularly to validating transmissions between a transmitter and a receiver by re-decoding transmissions.
II. Background
Wireless communication systems are widely deployed to provide various types of communication content such as, for example, voice, data, and so on. Typical wireless communication systems may be multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, . . . ). Examples of such multiple-access systems may include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, and the like.
Generally, wireless multiple-access communication systems may simultaneously support communication for multiple mobile devices. Each mobile device may communicate with one or more base stations via transmissions on forward and reverse links. The forward link (or downlink) refers to the communication link from base stations to mobile devices, and the reverse link (or uplink) refers to the communication link from mobile devices to base stations. Further, communications between mobile devices and base stations may be established via single-input single-output (SISO) systems, multiple-input single-output (MISO) systems, multiple-input multiple-output (MIMO) systems, and so forth.
MIMO systems commonly employ multiple (NT) transmit antennas and multiple (NR) receive antennas for data transmission. A MIMO channel formed by the NT transmit and NR receive antennas may be decomposed into NS independent channels, which may be referred to as spatial channels, where NS≦{NT,NR}. Each of the NS independent channels corresponds to a dimension. Moreover, MIMO systems may provide improved performance (e.g., increased spectral efficiency, higher throughput and/or greater reliability) if the additional dimensionalities created by the multiple transmit and received antennas are utilized.
MIMO systems may support various duplexing techniques to divide forward and reverse link communications over a common physical medium. For instance, frequency division duplex (FDD) systems may utilize disparate frequency regions for forward and reverse link communications. Further, in time division duplex (TDD) systems, forward and reverse link communications may employ a common frequency region. However, conventional techniques may provide limited or no feedback related to channel information.
Sending and receiving information is at the core of the communications industry. Recent increases in media content and applications have created high demand for efficiency and reliability in transmitting and receiving data. Hybrid automatic repeat request (H-ARQ) protocol is one mechanism for transmitting data that has been somewhat effective; however, there are obstacles to truly efficient and seamless transmission. Early solutions relied on power-hungry or highly complex routines which simply re-allocate resources (such as computational time and power) rather than solving the underlying problem.
H-ARQ and ACK protocols have furthered data transmissions, but there are shortcomings. The receiver sends an acknowledgment (ACK) to the transmitter to signal receipt of the data. Upon receiving the ACK, the transmitter begins transmission of the next data packet. This process continues until all data packets are transmitted and received. Under ideal conditions, the ACK is always received promptly by the transmitter, and there is little loss in throughput. However, ideal conditions rarely, if ever, exist. Frequently, the ACK is not received by the transmitter resulting in latency as the transmitter continues to send transmissions that have already been successfully received by the receiver. Worse, the transmitter can be instructed by a scheduler to suspend or postpone the data packet transmission when there is no substantial need to take such drastic measures.